Social distancing, face masks, hand washing, and other prophylactic measures have been promoted as effective, but what is the evidence?
An MIT study published in the Journal of the American Medical Association (JAMA) recently illustrates how coronavirus can travel much further in the air than we realized. It is a fascinating, disturbing, and very well constructed article about airborne viral transmission and wearing a mask, among other things. This does not prove that the virus can still be infectious after a specified distance, but it raises concerns that the 6-feet rule may not be sufficient, at least when indoors. This study is referenced in this Atlantic article. It is important to note that, although the greatest risk for transmission is no longer believed to be from contaminated surfaces, such as door knobs, hand washing and avoiding touching our face is still a critical preventative step we can take. Wearing a mask ‘properly’ can dramatically reduce face touching.
Another recent study in the prestigious medical journal, The Lancet, performed a systemic review of 172 studies, though without randomization and not fully adjusted in some cases. The results indicated, with a moderate degree of certainty, a large reduction in infection with at least 1 meter (3 feet) of physical distancing. Thus, at least 1 meter of distancing is strongly associated with protection, and distancing of up to 2 meters (6 feet) “might” be even more effective.
Wearing a mask and eye protective wear were both found to provide some protection, in particular the fitted respirator masks. There was a discussion about the biological plausibility of aerosolized virus, which might explain why respirator masks were found to be more effective, though the authors explain that the evidence from their meta-analyses provided a low degree of certainty for this, and that RNA detection does not necessarily imply that the virus is viable enough to cause infection. This study is discussed in lay terms in the following TIME article.
Click here to see a short YouTube video with one of the best explanation of why the N95 Respiratory Mask works so well.
One thing not discussed in the Lancet study was the very recent evidence that toilet flushing actually aerosolizes coronavirus.
The journal Physics of Fluids published research that indicates the following findings:
- An upward velocity of as much as 5 m/s is produced, which is certainly capable of expelling aerosol particles out of the toilet bowl.
- Some 40%–60% of the total number of particles can rise above the toilet seat to cause large-area spread, with the height of these particles reaching 106.5 cm from the ground.
- Even in the post-flushing period (35 to 70 seconds after the last flushing), the upward velocity of the diffused particles can reach 0.27 cm/s to 0.37 cm/s, and they continue to climb.
The authors of this paper advise the following safe procedures to adopt when using a toilet:
- Put the toilet lid down before flushing, which can basically prevent virus transmission.
- Clean the toilet seat before using it, since floating virus particles could have settled on its surface.
- Wash hands carefully after flushing, since virus particles may be present on the flush button and door handle
Conclusions
The evidence supports social distancing, mask wearing, and hand washing as evidence based and advisable for the prevention of SARS-CoV2 infection and resultant Covid-19. It also appears that public restrooms may be unsafe in certain settings, making it advisable to wear a respirator mask and eye protective gear, to close the lid before flushing, when possible, and to wash hands with soap or alcohol based cleansers before exiting, when available.
Because upwards of 50% of cases may be asymptomatic (
Click here to read our Blog about asymptomatic spread), it is still incredibly confusing to grasp disease severity. Hence, the relatively small percentage of cases that actually progress to severe illness are on the rise due to a 2nd wave of high infection rates.
In many hot spots we find ourselves again needing to stay home, social distance, wear masks, and wash hands in order to flatten the curve …. again. Even though most of us will fare well from Covid, there are genetic factors at play that we don’t yet understand. One example of this is
blood type A, which is a very short read. This speaks to the invisible susceptibility that is most frightening; when young healthy people succomb for no apparent reason. Thankfully, there are nearly a thousand genetic experts working together around the globe to share information in hopes of identifying the genetic codes that make some of us so vulnerable to this strain of the coronavirus.
Click here to read our Blog about this.
It appears that the most common sense strategy is for everyone to just play by the rules and stay safe until we learn who is most vulnerable, in particular from a genetic standpoint. This information will help us determine who should get first dibs on the emerging vaccines. Of the dozen or so unique vaccines in development, the first is slated to be approved sometime in the autumn, possibly as early as September. Stay tuned, we will be posting a Blog about Corona Vaccines in the very near future.
